Compact magnetic chuck



Aug. 10 1926.

F. L. SIMMONS COMPACT MAGNETIC CHUCK liled June 50, 1920 Patented Au..'1o,192e.l 1,595,692T

Umana STATES PATENT' ol-*Fica anni: LEROY lsrar'iieions, 0F WQONSOGKET,axiom; ISLAND, AssiGNoa To :una TART- Pnlmon MANUFACTURING CCMPANY. CFWooirsocxnrr, kRHODE 1sLAND,-` A Coa- PoRATIoN F RHODJ.' ISLAN v COMPACTMAGNETIC CHUCK.

application nieu June so, 1920. serial No. 392,951.

The present invention 'relates broadly to structions Where the Asidewalls of the chuck electrical devices 11nd more particularly to form apart of the magnetic circuit the mag- 55 a magnetic chuck. netic pathsare not uniform in the side walls The yprincipal objectief the presentinin view of the fact that Where the screws 6 vention is a compacttntagnetic chuck Wherepass through the side walls areynot of uniin thecoil is securel heldin place and the forni thickness. It is particularlydesirable parte are assembled without vindividual asin a magnetic chuckto have the magnetic 60 semblyserews. holding power uniform over theface of the Afhrther and important object of the chucln Furthermore,such prior art con- 10 presentinvention isa magnetic chuck havingstructions have requiredk considerable `fitting the contact membersmolded directly into a in that there is the necessity ofcoordinatin'pant of the body of the chuck. the openings in the bodyof the chuckwit65 A still further and important object of those in the part to besecured, usually thelv the present inventieve is a magnetic chuck taceplate, and the assembly is of suoli wherein the face ate is screwthreaded to nature that the parts are securely clamped the body Wall oft efch'ucjk or to the housing together only at the points where thescrews forthe energizingeoil, and clamps the coil are seated.v Magneticchucks are frequently 70 in place. y used to hold r-work on a grindingmachine A further and important object of the using a grinding fluid soythat the chuck is present invention is `the arrangement ot' submergedinliquid. Itis very essentialy face plate pole pieces inlsuch manner asto that all' joints shall be peidectlyv tight to pr uce a plurality ofindividualized areas prevent any liquid from entering the body by meansof two pole ypiece members, one of of the chuck. Where screw boltshavebeeii which is supported on the shell, and the usedyin assembling inthe prior art in 'most other of Whi is supported upon a central casesthere Was but one single-joint between core pole. they parts' heldtogetherby thescre'w bolts @ther and further .obiectsf ofthe. presentandthis joint was liable toj'le'ak. 80 y invention will in pat'be obviousand will in It has also been the custom of the prior part lbe' pointedout hveenafter by reference art to provide screw attached electriecom tethe accompanying drawingswherein like tac-t members which tendV to work.loose and parts are represented' by hkekcharacters break the contact..It` the contact is broken thrqu hout the several guresthereo. v thechuck immediately looses its holdingfea yRefizing that' the presentinvention may power',V the Work is released,and there is the be embodiedin constructions otherthaur liability of ythev workbein'g spoiled,.aswell those specifically shown, it is desired that the asy greatliability of tool breakage. K specific disclosure herewith shall be conthas also been customaryin the prior sidered as illustrative and not inthe limiting art to arrangey various types of pole piece im sense. Yforms, inmost cases, withoutl any special Figure 1 is a sectional viewillustrating consideration concerning the metalmass'ada chuck embodyingthe present invention; jacent the pole pieces. In order to maintainFigure 2 is a view of one form of kface av uniform field it isparticularly desirable plate embodying the presentk invention; that thewidth of the magnetizable metal 'a5 Figure 3 is a View of' ak differentform mass at the Work face shall be approximately of face plate also e"hodying the present equal on theavarious pole pieces in order toyinvention. v p maintain al uniform field, and itis alsoV par-`Heretofore in they arty of magneticchucks ticularly desirable that thelines separating it has been customary to assemblel the chucks the. polepieces shall be disposed at substanl 100 by means ofvscrews passedthrough the body tially right angles to the forces' to which wall of thechuck. In certainiorms these the work will be subjected when on the facescrews have Y been inserted lengthwise plate. In a rotary ch'u'ckfit is;therefore, thron h the side body walls and' screwy desirable to havecertain linesarrangedcirrthrea ed into the top orfabe late, therebycumterentially of the chuck to resistcentrif m5 locking thepartstogether." n' such con'- uga'l forces tendingv to throw the workfrom Cil the chuck tace, which forces act radially, and it is alsodesirable that certain lines shall be radial lines in order to resistcircumferential forces established in the work by the acti-on oi' thecutting member or tool while the chuck is rotating. There the chuck ismade up of a detachable tace plate and a central core piece and aconcentric surrounding wall, one ot which comprises one core pole andthe other ot which com prises the other core pole, it is particularlylesirable that the tace plate be constructed in such manner that onegroup of poles sustained by the central core pieceand the v other groupot poles is sustained by the wall whereby the body ot the chuckcompletely sustains all forces presented at right angles to the face ot'the chuck. This prevents any tendency ot the pole piece members toloosen one trom the other.

The present invention overcomes the dit iiculties of the known art byproviding a very simple magnetic chuck which may be embodied in acylindical body having an npstanding central core pole piece adapted tobe surrounded by an energizing member which may comprise one or morecoils or insulated conductors. The face plate is cured tothe bodyportion without the use ot individual screw bolts and may be attached tothe body portion by means otI screw threads on the face plate member andon the body portion. This construction provides for at least twoindependent seals at the joint between the body portion and thetaceplate so that such construction is easily waterprooted. The faceplate preferably is comprised of two pole piece members, one of which isprovided with openings through which projections from the other polepiece member extend, with nonmagnetic material separating the polepieces one from the other and with a portion of the openings beingconcentric with the axis of the tace plate and another portion beingradial. This resists both the radial and circumferential Jorcos to whichwork on a rotary chuck is usually subjected. The body wall ot' thechuck, preferably at the back. may be provided with a retention membersuch as a groove for the contac' devices. Preferably t-he contact ringsare set in position and then moldable insulating material is positionedin the groove and around the bases of the contact rings so that thecontact member is molded directly into the body portion of the chuck andis therefore very securely attached to the chuck and there ispractically no possibility of such member becoming loosened. lVhilevarious insulating` compounds may be used, j n'eerably the compoundemployed is a phenol condensation product such as bakelite orcondensite.

Referring now to the drawings, one embodiment of the present inventioncomprises a chuck having a body portion 1 which preferably iscylindrical in iorm and is provided with a central cylindrical core 2,which may be integral with the back wall 4 which carries the side wall5. The sine wall may be screw threaded as at t and the back wallpreferably is provided with concentric ribs and 8 which are undercut toprovide retention :tor the contact ring base. The tace plate 9preferably comprises a plurality ot pole piece members which may be twoin number, such as l() and 11. The pole piece member 10 pro vided with aplurality ot openings through which projections 12 from the pole piecemember 11 extend. The pole pieces 1() and 11 spaced apart and the spaceis lilled "i h non-magnetic material 14 which magnercally insulates onepole'piece 'trom the other and which separates the projections on thepole piece 11 from the side walls ci the openings in the pole piece 10.thereby providing a plurality of magnetically sepaated areas toconstitute ditierently magnctized pole pieces at the work tace of thechuck. he non-magnetic material presents ace oi the tace plate with aportion ot' each ure being substantially concentric to the a-ns ot thechuck and another portion being ubstantially radial to this axis. Thisform tends to create magnetic Zones that resist movement ot the workacross the magnetic` lines so that the work is held against both radialand circumferential forces. In Figure 2 the iigures are made up otisolated segments ot concentric rings, with certain ot the segments tiedtogether by substantially radial bars. In Figure 3 the geometric figuresare likewise made up of isolated segments of concentric rings with theradial members bisecting the ring portions. Preferably the pole piece1() is provided with an extension 15 which is screw threaded to engagethe screw threads G on the side wall 5. This extension 15 may beundercut as at 16 to facilitate the threading operation and also toprovide an accurate seat between the under side ot the pole piece 10 andthe end or edge of the side wall Furthermore. the undercut groove 'llimay be utilized for retaining a suitable gasket where a very secure sealis desired. The face plate may be provided with openings 17 for thereception ot' a spanner wrench or similar device so that the face platemay be securely seated against the body wall by means ot the screwthreads. This construction it will be observed provides a double sealfor the joints between the tace plate and the body in that the screwthread portion forms a side seal and the end of the side wall and theend of the pole piece 10 forms a top seal. Furthercd geometric iigureson the work sur-- Hin more, in View of the fact that the screw threadsare continuous around the side of the chuck, the sealing forces aresubstantially. uniform on all parts yso that a very accurate and `secure`joint is attained. In order to prevent any possibility of the faceplate unscrewing a stub screw such as 18 may be seated through theextension 15 against the side wall 5. A suitable energizing coil orcoils 19 is securely mounted in position on the central corer 2 and maybe supported by insulatino washers 20 and 21, which are securely campedin place against the coil when the face plate is screwed into place. Asuitable opening is provided in the back wall of the chuck between theconcentric ribs 7 and 8. The contact rings 22 and 24 are positionedbetween the; ribs 7 and l8 and the terminals of the coil 19 are broughtthrough the said opening and connected with the contact rings. Thegroove formed between the undercut concentric vribs 7 and 8 and theopening through Whichthecontacts extend is then filled with moldedinsulating material, for example, ya phenol condensation product such asbakehte or condensite and the contact rings are, therefore, moldeddirectly into position in the insulating 'base 25 which is securely heldbetween the undercut ribs 7 and 8. The back of the chuck is recessed asat 26 and provided with stub scnew openings 27 which are adapted toreceive stub` screws to secure the chuck in position on the head of avsuitable machine such as a grinder or the like.

Fromfthe oregoingit will be noted that the present chuck comprises anexceedingly compact rigid construction adapted to withstand severe usagewithout injury to the chuck and because of the fact there is but asingle joint in the shell of the chuck, which joint is double sealed,the chuck is admirably adapted for Wet grinding or like work where thechuck is submerged in liquid.

Having thus what I claim is:

l. In a magnetic chuck, the combination of a body portion forming areceptacle for electromagnetic means. electromagnetic means within thebody portion, a face plate adapted to cooperate with the body portion toseal the body portion and to clamp said electromagnetic means securelyin place, and a screw threaded connection o eratively connecting theface plate with the body portion.

2. In a magnetic chuck, the combination of a body portion forming areceptacle for electromagnetic means, electromagnetic means within thebody portion, a core post in the center of the body portion, a faceplate contacting with the post and adapted to cooperate with the bodyportion to seal described my invention,

the body portion, and a screw threaded connection operatively connectingthe face plate with the body portion, said face platecomprising a seriesof pole pieces cooperating with said post and a complementary pole piecesupported by the edge of the body portion.

A magneticchuck comprising a hollow body portion, a central postintegral with the body portion, electromagnetic means ccu'iln'ising acoil surrounding the post within said body portion, and a work-*faceprovided with a plurality of pole pieces separated by non-magneticmaterial and adapted to be magnetizedwhen the electromagnetic means isenergized, said pole pieces being arranged into al series of polepiecesy cooperating with said post and a pole piece supported by thebody wall of the chuck.

Lil. In a magnetic chuck, the combination 'oif a body portion, a pair ofoverhanging ianges on said body portion, collector rings between saidflanges, and a moldable insulating body interlocked with said flangesand imbedding a portion of said rings whereby the collector unit ismolded in positon on the chuck.

In a magnetic chuck, the combination of a body portion, a pair offlanges on said body portion having inturned edges, colecior ringsbetween said flanges, and an insulating body molded into positionybetween said flanges and retained in position by said inturned edges,and imbedding a portion of said rings whereby the collector unit ismolded in position on thechuck.

6. In a magnetic chuck, electromagnetic means in combination withcollector' means comprising a plurality of collector rings, an annularmoldable base in which a portion of' said collector rings is imbedded,an annular anchoring means carried by the chuck and engaging theannularbase throughout at least a substantial portion of itscircumference to secure said base to the chuck.

7. In a magnetic chuck, an annular co1- lector ring base, interlockingmembers car ried by the chuck, with the sides of said collector ringbase molded into engagement with said interlocking members, saidinterlocking members engaging said base annularly about itscircumference, and a plurality of' collector rings imbedded in saidbase, said base comprising a phenol condensation product.

8. A magnetic chuck, a. body portion, electromagnetic means within thebody portion, a collector ring unit, conductors for leading a suitablecurrent=to said electromagnetic means, said collector ring unitcomprising aninsulating base molded in position on the body portion, anintegral extension on said base extending into the body portion andenclosing a portion of said condoctors, and a plurality of collectorrings carried by said base and connected to said Conductors.

S). ln a rotaryv magnetic ehuel, a bot y portion termino a shell, a postin the oenter oi sail shes, etromagnetio energizing inea-.is a :lage p1o comprising tvvo nieml' s, one ol which is adapted to be energized tocomprise one pole, the other of ivhieh is adapted to be energized tocomprise an opptsi" `iole, one ol' said members beingy provided u iopenings, projections on the other inen 2r ad; @tee to extend throughsaid ope-niiV1 nonninamaterial separating one o said embers 'from theothe; and sep-ai j 'le outline oit' Seid the Work 'jaee the it i "singclosed geon'ietrie figures with a portion ot eaoh ligero being'concentrie to the axis of the ebnen and a other portion being'ubstantiall)v radial to the axis of the chuck, a serevv threadedlioijoix betr-:een the face plate ant the body portion, one ot said inemng by said post and the other or. said nembers being supported on thesneil ot the body.

l0. A magnetic chuck compi in eo 1 binetion a body portion, e means forenergizing said when said means are energized by able electric current.a 'ieee plate having parallel es and Comprising tivo pole piece i""egralwith said body pory t sind pole piece members being with openings, 'theother or' said piece. members being` provided With p ole projectionsextending through said openings, and nomnagnetie material separatingsaid pole piece members and forming closet geometrie figures at the-Work face of the tace plate, and with the base tor said projectionsextending beneath a portion of the lpole piece member provided with theopenings.

11. A face plate for a magnetic chuck having substantially parallelsides and coinprising tivo pole piece members7 one of said pole piecemembers being provided with openings, the other olf said pole pieceniembers being provided -with projections extending through saidopenings, and with said projections on a common base extending beneath aportion of the pole pieee meinber provided vv i the openings, andnonmagnetic mate iai separating said pole piece members and ormingclosed geometrie figures at the \v\ i the face plate.

l2. A face plate ior a magnetic chuck having parallel sides andComprising pole piece members one oit said pole piece mem bers beingprati Jl with openings, another or said pole oieee members beingprovided with project mounted upon a common base and ext-@ding under aportion oi said other pole p'r` and through said openings, and nonni-agmaterial separating said pole piece ine is and forming closed geometrieligure., tt the work 'tace of the face plate, with the rsidth of themagnetic ma- FRANK LEROY SIMMONS.

